The present invention relates to a device for floccing a water-chemical mixture produced during oil or gas well drilling.
When drilling an oil or gas well, water and chemicals are circulated through the well to assist in the removal of mud, particulates and other purposes. It has been a challenge to clean this water/chemical mixture before pumping it down the wellhead. This process is referred to as xe2x80x9cto floc or floccingxe2x80x9d.
It is known to use for floccing a very expensive centrifugal removal system, that removes suspended particulates through centrifugal force. Another known system includes a series of one, two or more horizontal settling type tanks. These tanks will allow the particulate to settle over a period of time. The tanks are usually squared in shape, and several tanks at times are necessary in sequence to sufficiently clean the fluid. Due to the square design, it is very difficult and dangerous to clean the tanks. A worker must enter the tank and shovel out the refuse that has settled.
Accordingly, it is an object of the present invention to provide a device for floccing a water-chemical mixture produced during oil or gas well drilling, which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated, in a device for floccing a water-chemical mixture produced during oil or gas well drilling, which has a tank with a substantially cylindrical vertical wall having a central axis, and a bottom located under said wall, wherein a vertical height of said tank is significantly larger than a horizontal cross-section of said tank; means for supplying a water-chemical mixture into said tank from a top of said tank into a tank interior, so that a solid fraction of the mixture settles on said bottom; and means for withdrawing a liquid fraction of the mixture from said tank.
When the device is designed in accordance with the present invention the vertical tank utilizes gravity, to compress solids which settle in the tank 5-6 times more than in a horizontal tank which is utilized in the prior art. The device is more economical and more environmental friendly. It uses less water because of squeezing action of the solids due to gravity and also it uses less chemicals because of less water being used. Also, less amount of solids volume being spread due to solids being more dense for land spreading. It also has less load to be hauled because one vertical tank will perform the action of two horizontal tanks. As solids are settled down in the tank during drilling of the well, the solids are allowed to pile up much higher than in the horizontal tanks. In turn, this allows the gravity to squeeze the water out of the settlings, making a much more dense flocced solids to be hauled to a spread field or to a sump location. The horizontal tank of the prior art uses 4-5 feet of floc compression, while the vertical floc tank in accordance with the present invention uses up to 20 feet of floc compression.